The diversity of modern technical applications creates a need for efficient electronic components and integrated circuits for use therein. Capacitors are a fundamental component used for filtering, decoupling, bypassing and other aspects of such modern applications which may include wireless communications, high-speed processing, networking, circuit switching and many other applications. A dramatic increase in the speed and packing density of integrated circuits requires advancements in decoupling capacitor technology. When high-capacitance decoupling capacitors are subjected to the high frequencies of many present applications, performance characteristics become increasingly more important. Since capacitors are fundamental to such a wide variety of applications, their precision and efficiency is imperative. Many specific aspects of capacitor design have thus been a focus for improving the performance characteristics of capacitors.
A wide variety of conventional capacitors are available on the market today, and each provides a unique combination of performance characteristics well-suited for particular applications. For example, electrolytic capacitors, such as tantalum capacitors, are traditionally employed in applications where a high capacitance value and overall device compactness are required. Multilayer ceramic capacitors (MLCCs) are typically quite effective for frequency filtering applications. It is quite common that these and other particular capacitor types will be used in a single integrated circuit environment. In such instances, the different capacitors may be connected in parallel on a printed circuit board (PCB) as discrete components. This requires a relatively large amount of circuit space and separate mounting pads for each capacitor. As a result, efforts continue to strive for component miniaturization, orientation efficiency and other ways to save space and maximize board real estate in a PCB environment.
It may also be desirable to improve other capacitor performance characteristics, such as ESR (Equivalent Series Resistance), which is the inherent resistance value of a capacitor. Because theoretical capacitors do not actually include any resistance, it is often desirable to create a capacitor with low ESR. The need for minimal ESR is especially evident in decoupling capacitor applications. Increased ESR can increase the ripple voltage and power dissipation for a given capacitance value. This is related to the RC time constant of a capacitor and contributes to the need for low capacitor ESR.
Another capacitor characteristic that may affect circuit applications is piezoelectric noise, which is prevalent in many MLCC applications. Low level piezoelectric noise may be generated when the capacitor ceramics are subjected to alternate voltages, which can cause mechanical vibrations in the capacitor. The inherent nature of the ceramic material converts the mechanical vibrations to generally low-level electrical noise. Significant amounts of piezoelectric noise can have an effect on signal quality, especially in high frequency applications. As such, it is often desirable to reduce piezoelectric noise levels in circuit applications.
Thus, a need currently exists for an integrated capacitor assembly that exhibits a broad range of electrical properties.